This invention relates to a seat recliner for a vehicle for rotatably mounting a seat back as a backrest relative to a seat cushion as a seat face.
This type of seat recliner for vehicle includes a frame to be mounted on a base plate on a seat cushion side, for example. The seat recliner includes a lid to be mounted on an arm plate on a seat back side. The frame and the lid are made rotatable relatively to each other. An external gear (teeth) of a locking-member on the frame is engaged with (i.e. meshed with) an internal gear on an inner peripheral face of the lid. This engagement prevents relative rotation of the frame and the lid, thereby supporting the seat back in a position at a given angle. In this concern, see Japanese Unexamined Patent Publications No. 2002-10847 and No. 2002-291563, for example.
In the frame, a pivot and a guide are provided in the vicinity of the internal gear. The locking-member has a recessed bearing, which is slidably engaged with the pivot. The locking-member has an arcuate retaining face, which slidably abuts on a guide face of the guide and is coaxial with the bearing. The guide face is formed from the vicinity of the internal gear toward the inside of the internal gear, into an arc shape which is coaxial with the pivot. The inside of the internal gear includes a cam plate for driving the locking-member outward, so as to engage the external gear with the internal gear.